Front-end vehicle structure

ABSTRACT

A front-end vehicle structure for a motor vehicle, in particular for a commercial vehicle, includes two longitudinal members and two crash box elements. It is essential to the invention that two connecting members are provided which each connect one of the longitudinal members to the associated crash box, element. Each of the connecting members is assembled from an inner shell, an upper shell, and a lower shell. In each case, the upper shell and the lower shell reinforce the inner shell.

BACKGROUND AND SUMMARY OF THE INVENTION

This invention relates to a front-end vehicle structure for a motorvehicle, in particular for a commercial vehicle.

Commercial vehicles of conventional design are generally constructed insuch a manner that two frame longitudinal members are connected to framecross members and in such a manner form the supporting frame, the framelongitudinal members being brought as far as a front and/or a rearbumper and generally being connected to an end cross member and thebumper via a crash box part. Particularly in the region of the frontend, the supporting frame, in addition to the supporting function as aframe component, also has to ensure an integrating function, for examplefor receiving the front axle and the drive unit.

On account of the components which are adapted to the particular overallweight and are intended for optimizing the payload capacity, thecomponents differ greatly in dimensions, depending on the vehicle type.This different dimensioning results in complex components, theproduction of which is associated with high costs.

German document DE 42 40 344 A1 discloses an auxiliary frame for a truckchassis. The auxiliary frame is intended to cover various chassis framesin which an angled portion of the longitudinal members is situated atvarious locations. The auxiliary frame uses longitudinal members with adifferent profile in the longitudinal direction. In the front region,the longitudinal member has a U-profile and, in the remaining region, ithas a Z-profile. The upper limb of the Z-profile adjoins the upper limbof the U-profile; by contrast, the lower limb of the Z-profile is offsetin the transverse direction with respect to the lower limb of theU-profile, to be precise toward the adjacent longitudinal member. Thus,the offset, lower limbs of the Z-profiles of adjacent longitudinalmembers form a smaller clear width of the auxiliary frame, and the lowerlimbs of the U-profiles of adjacent longitudinal members form a largerclear width of the auxiliary frame. Different truck chassis cantherefore be covered using one size of this auxiliary frame.

German document DE 40 06 418 A1 discloses a supporting frame for atruck. The supporting frame essentially comprises frame longitudinalmembers and frame cross members and also a spherical or composite linkaxle. Furthermore, it has a front cross member which extends beyond theends of the longitudinal members over the width of the vehicle, isarranged at a distance from the bumper and is designed as the front-endvehicle module. On its side facing the center of the vehicle, thefront-end vehicle module is connected to the ends of the framelongitudinal member and on its side facing in the direction of travel isconnected to the bumper. The crank or composite link axle is mounted onthe front-end vehicle module in such a manner that its angled portionengages around the end of the engine.

As a result of different wheel bases, the arrangement of leading ortrailing axles and different heights of the frame longitudinal members,a multiplicity of variations of the commercial vehicle does not ariseuntil the construction stage. The front-end vehicle module per se can bepre-assembled in relatively large piece numbers and stored, and thusenables conveyor line assembly.

German document DE 42 28 314 A1 discloses a chassis for a truck. Thesupporting structure of a truck which comprises a front end and a rearend is in three parts and comprises a central supporting framework, abow-shaped front frame and a frame longitudinal member structuresupporting the superstructures. The central supporting framework engagesaround the drive units and is essentially arranged in the completeshadow of the front wheels. Furthermore, it has a downwardly open,pannier-like shape. On its rear side, the central supporting frameworkis connected fixedly, but releasably, to the frame longitudinal memberstructure supporting the superstructures and, on its front side, isconnected to a front, bow-shaped front frame which partially supportsthe driver cab and supports the front parts. In this manner, differentrear ends can be adapted to the front end, which is always standard,even with the frame longitudinal member structure differing in height.However, nothing is disclosed in German document DE 42 28 314 A1concerning structural details of the front end.

U.S. Pat. No. 6,328,377 B1 discloses a front-end vehicle structure ofthe type mentioned at the beginning which has two longitudinal membersand two crash box elements. Furthermore, two connecting members areprovided which each connect one of the longitudinal members to theassociated crash box element. The connecting members can be assembled ineach case from an inner part and, in order to reinforce the inner part,from an upper part and a lower part. In the case of the known front-endvehicle structure, the inner part is formed by a hollow profile whilethe lower part and upper part are in each case formed by an L-profile.In this case, the L-profiles completely engage around the circumferenceof the hollow profile.

U.S. Pat. No. 5,913,565 discloses a further front-end vehicle structure,in which, on each side of the vehicle, a connecting member connects alongitudinal member to a crash box element. In this case, the connectingmembers are in each case formed by a multipart hollow profile which canbe reinforced with the aid of a reinforcing profile. The reinforcingprofile here is largely matched to the profile of the connecting memberand is optionally arranged on the outside thereof or on the insidethereof.

Japanese document 10-287269 shows a wide front-end vehicle structure, inwhich a thin-walled, front extruded profile is connected in a connectingregion to a rear, thick-walled extruded profile. In the connectingregion, U-shaped or L-shaped or C-shaped reinforcing elements are fittedfrom below or from above in such a manner that the reinforcing elementsengage laterally both over the front and the rear extruded profile inthe connecting region. By this means, the connecting region can beeffectively reinforced.

The present invention is concerned with the problem of providing animproved embodiment of a front-end vehicle structure and of therebysimplifying the production process.

This problem is solved by the subject matter of the invention.Advantageous embodiments are the subject matter of the dependent claims.

The invention is based on the general concept of designing a front-endvehicle structure for a motor vehicle, in particular for a commercialvehicle, in such a manner that the production of very complexcomponents, such as, for example, a pre-assembleable front-end vehiclestructure, is possible on the basis of simple sheet-metal geometries.

This is achieved by providing two connecting members which each connectone of the longitudinal members to the associated crash box element, theconnecting members being assembled in each case from three parts, namelyfrom an inner shell (inner part) and an upper shell (upper part or uppersheet-metal strip) and a lower shell (lower part or lower sheet-metalstrip) which each reinforce the inner shell.

The inner shell, the upper shell and the lower shell or the inner part,the upper part and the lower part are expediently designed as bentsheet-metal parts, the upper shell and the lower shell being arrangedessentially on the edge of the inner shell and transversely with respectto it.

The separation of the supporting structure into a plurality ofsheet-metal parts means that the latter are to be deformed only as bentsheet-metal parts and are therefore simple to manufacture. In the blank,the components for the left and right connecting members are identicaland have merely to be tilted in a mirror-inverted manner. This firstlyresults in a simplified production of the sheet-metal parts andsecondly, by means of a simple bending operation, a drawing operationwhich is problematic in the case of thinner sheet-metal components andseverely strains the material is avoided.

The invention affords further advantages if each connecting member isdesigned in a manner such that it can be pushed by its front end intothe associated crash box element and/or by a rear end into theassociated longitudinal member. The separation of the supportingstructure in the region of a front axle makes it possible to influencethe length of the vehicle by appropriately varying the length of theconnecting members.

Furthermore, provision can be made for the connecting members and thelongitudinal members each to have a C-profile and for an external sizeof the respective connecting member to correspond, in the assembledstate, with an internal size of the respective longitudinal member. Thissimplifies the assembly of the front-end vehicle structure and, withrespect to a subsequent transmission of force, such as, for example, atransmission of transverse forces, achieves significant advantages incomparison to conventional constructions.

One particularly advantageous refinement of the solution according tothe invention is characterized in that the inner shell, the upper shelland the lower shell are connected by means of welds extending along thebent-over edge sections. Accordingly, a weld bead or weld seam runsalong the bent-over edge sections of the inner shell, which edgesections run parallel to the upper or lower shell and bear extensivelyagainst it, and therefore closes a gap situated between or the uppershell or lower shell and the inner shell and thus prevents theparticularly problematic gap corrosion. Since the supporting structureof the vehicle is exposed virtually without any protection to the spraywater occurring under the vehicle, which water, particularly in thewinter months, is additionally contaminated by chlorides, the qualityand, in association therewith, the service life of the commercialvehicle is increased by the encircling weld bead.

One particularly favorable development of the solution according to theinvention is characterized in that the inner shell, the upper shell andthe lower shell can be formed with an identical and/or differentsheet-metal thickness. Commercial vehicles are produced for a very widevariety of spheres of use, such as, for example, for transportation ofheavy loads or for conveying people, and accordingly require supportingstructures of differing thickness. Account is taken of this circumstancein a particularly favorable manner by the use of identical and/ordifferent sheet-metal thicknesses for the formation of the connectingmembers. Thus, the use of thick metal sheets is favorable particularlyfor vehicles having high payloads, while for lighter vehicles smallersheet-metal thicknesses are sufficient. This enables a flexible reactionto the demands imposed on the vehicles without having to undertakerelatively great changes during the production process.

Provision can expediently be made for the edge sections to be designedin a manner such that they are separated from one another by means ofincisions. The incisions on the inner shell bring about a simplificationof the forming process, in which the edge sections of the inner shellare bent over at right angles. Since the bent-over edge sections are notarranged parallel to one another, the material without incisions wouldbe subject to considerable drawing operations and therefore loads. Thesecan be entirely avoided by the abovementioned incisions, which, inaddition to the abovementioned simplification of the production process,also protects the material.

One advantageous development is that the front-end vehicle structure isdesigned in the region of the connecting members for receiving a rigidaxle or an individual wheel suspension. Depending in each case on thesubsequent intended use of the vehicle, whether, for example, as aconstruction site vehicle or as a bus, the solution according to theinvention makes it possible to design the front-end vehicle structure ina flexible manner, thus permitting, for example, the installation of arigid axle for heavy-duty vehicles and the installation of an individualwheel suspension for lighter vehicles.

Further important features and advantages of the invention emerge fromthe subclaims, from the drawings and from the associated descriptions ofthe figures with reference to the drawings.

It goes without saying that the features mentioned above and those whichhave yet to be explained below can be used not only in the respectivelystated combination but also in different combinations or on their ownwithout departing from the scope of the present invention.

Preferred exemplary embodiments of the invention are illustrated in thedrawings and are explained in more detail in the description below, withthe same reference numbers referring to identical or similar orfunctionally identical components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a front-end vehicle structureaccording to the invention with connecting members,

FIG. 2 shows a view similar to FIG. 1, but from a different perspective,and

FIG. 3 shows an exploded illustration of one of the connecting members.

DETAILED DESCRIPTION OF THE INVENTION

According to FIG. 1, a front-end vehicle structure 1 according to theinvention shows two connecting members 13 and 13′ which extendessentially parallel to a vehicle longitudinal direction 14, which issymbolized by an arrow. The connecting members 13, 13′ are arrangedupright between a rear end of a first crash box part 6 and a front endof a right longitudinal member 3, and between a rear end of a secondcrash box part 10 and a front end of a left longitudinal member 2 andare spaced apart from each other in the horizontal direction.

At a respective front end of the first crash box part 6 and of thesecond crash box part 10, said crash box parts are connected to eachother in the transverse direction of the vehicle via a bumper 11. Theconnecting members 13, 13′ form a region of a subsequent front axlemount and are connected to each other in the transverse direction of thevehicle via a cross member 9. The connecting members 13, 13′ can bedesigned either for receiving a rigid axle or an individual wheelsuspension.

In the region of the front-end vehicle structure 1 that is illustratedin FIG. 1 and FIG. 2, a driving device (not shown here) of thecommercial vehicle is usually arranged between the two connectingmembers 13, 13′. A driving device of this type generally comprises aninternal combustion engine and a transmission, for which reason theconnecting members 13, 13′ are widened transversely with respect to thelongitudinal direction 14 of the vehicle in the direction of a front endof the commercial vehicle.

The front-end vehicle structure 1 is constructed in a mirror-invertedmanner with respect to a plane running vertically through thelongitudinal center of the vehicle, with the result that just one halfis described in detail below. However, the same accordingly applies forthe other half.

According to an exploded illustration in FIG. 3, the connection member13 is composed of essentially three components.

These components comprise, firstly, an inner shell 7 which is positionedin an upright manner and has, on its upper and on its lower edge,respective edge sections 8 which are bent over at right angles to theplane of the shell and are angled in the direction of the abovementionedmirror plane about a buckling axis 17 running in the plane of the shelland parallel to the respective edge. The individual edge sections 8 areseparated from one another by incisions 15 which have the effect that,during the bending operation, the material is bent only about one axis(cf. FIG. 3, number 17) and therefore multiaxial drawing operationswhich greatly strain the material are avoided.

Secondly, these components comprise an upper shell 5, which runs alongparallel to the upper edge sections 8 and bears extensively against themand is connected hereto, and a lower shell 4, which runs along parallelto the lower edge sections 8, bears extensively against them and isconnected hereto.

The upper shell 5 and the lower shell 4 are designed in each case assheet-metal strips which are bent, corresponding to the respective edgesections 8 of the inner shell 7, about a plurality of bending axes 16which are arranged parallel to one another and are spaced apart from oneanother and run orthogonally to the plane of the inner shell 7 and ofwhich one is shown in FIG. 3 by way of example (cf. FIG. 3, number 16).

In this case, the upper shell 5 and the lower shell 4 are arranged onthe inner shell 7 in such a manner that they bear parallel to thesurface of the edge sections 8 of the inner shell 7 with a longitudinaledge 19 flush against the buckling axis 17 and, as a result, form acontinuous, planar surface on the outside of the connecting member 13,which side faces away from the abovementioned mirror plane.

The upper shell 5 and the lower shell 4 are connected to the inner shell7 in each case by means of welds which extend along the edge sections 8and which, in a favorable manner, close a possibly occurring gap betweenthe upper shell 5 and the inner shell 7 or the lower shell 4 and theinner shell 7 and therefore eliminate the risk of gap corrosion. At thesame time, a weld bead arranged in an encircling manner is used toprovide a fixed connection of the three shells 4, 5 and 7, whichincreases the rigidity of the connecting member 13.

According to FIG. 3, the assembled connecting member 13 is pushed intothe longitudinal member 2 in such a manner that the open side of theC-shaped profile, which is formed by the inner shell 7 and the upper andlower shells 4, 5, point in the same direction, namely in the directionof the above-described mirror plane, in the case of the connectingmember 13 and in the case of the longitudinal member 2.

In this case, the connecting member 13 is assembled in such a mannerthat it can be pushed into the longitudinal member 2 in a preciselyfitting manner, as a result of which transverse forces and moments canbe transmitted. That is to say, an external size of the connectingmember 13 corresponds, in the assembled state, to an internal size ofthe left longitudinal member 2.

The connection between the connecting member 13 and the leftlongitudinal member 2 takes place, for example, by means of screwconnections or welds (not illustrated in FIG. 3).

According to FIG. 2, a plurality of brackets 12 are arranged on theconnecting member 13 or on the inner shell 7 and are designed forreceiving a bearing 20 (illustrated in FIG. 1) of an upper transverselink 21 and for reinforcing the connecting member 13. The connectionbetween the inner shell 7 and the brackets 12 likewise takes place, forexample, by means of screw connections, rivet connections or welds.

According to FIG. 3, the inner shell 7 has a plurality of cutouts 18through which components of the underbody structure or of the transverselink 21 can be guided. An adaptation to different load situations, asoccur in the case of different vehicle types and/or in the case of adifferent intended use of the vehicle, takes place in particular byvarying the sheet-metal thickness of the individual shells 4, 5 and 7and, if appropriate, of the brackets 12.

By separating the connecting member 13 into the three shells 4, 5 and 7mentioned, it is possible to produce the latter individually as bentsheet-metal parts and therefore to manufacture them in a simple manner.Furthermore, the front-end vehicle structure 1 with the components whichcan be attached thereto forms a pre-assembleable unit which can bepre-assembled within the context of a pre-assembly operation and can befastened to the longitudinal members 2, 3 or the crash box parts 6, 10within the context of a final assembly operation.

In summary, the invention can essentially be characterized as follows:

The connecting member 13 is essentially composed of three components:the inner shell 7 which is positioned in an upright manner and has edgesections 8, which are bent over at right angles on the edge, and theupper and lower shells 4 and 5 which run along parallel to them and bearextensively against them.

The upper shell 5 and the lower shell 4 are connected to the inner shell7 in each case by seams of welds which are closed in an encirclingmanner and extend along the edge sections 8, eliminate the risk of gapcorrosion and increase the rigidity of the connecting member 13.

The assembled connecting member 13 can be pushed into the longitudinalmember 2 in a precisely fitting manner and can be screwed or welded tothe latter.

By separating the connecting member 13 into three components, namely theinner shell 7, the upper shell 5 and the lower shell 4, it is possibleto produce them as bent sheet-metal parts and to manufacture them in asimple manner without subjecting the material to a multidimensionaldrawing operation.

The front-end vehicle structure 1 can be designed optionally forreceiving a rigid axle or an individual wheel suspension. An adaptationto different load situations expediently takes place by varying thesheet-metal thickness of the inner shell 7, the upper shell 5 and/or thelower shell 4 and the brackets 12.

1-9. (canceled)
 10. A front-end vehicle structure for a motor vehicle,in particular for a commercial vehicle, comprising: two longitudinalmembers, two crash box elements, and two connecting members, each ofsaid connecting members connecting one of the longitudinal members to anassociated one of the crash box elements, wherein each of the connectingmembers is assembled from an inner part and, in order to reinforce theinner part, an upper part and a lower part, wherein the inner part is aninner shell which is essentially positioned in an upright manner andhas, at an upper end, bent-over, upper edge sections and, at a lowerend, further bent-over, lower edge sections, wherein the upper part isan upper sheet-metal strip which runs parallel to the upper edgesections, bears extensively against the upper edge sections, and isconnected thereto, and wherein the lower part is a lower sheet-metalstrip which runs parallel to the lower edge sections, bears extensivelyagainst the lower edge sections, and is connected thereto.
 11. Thefront-end vehicle structure as claimed in claim 10, wherein the innerpart, the upper part, and the lower part are designed as bentsheet-metal parts, and wherein the upper part and the lower part arearranged essentially on an edge of the inner part and transverselythereto.
 12. The front-end vehicle structure as claimed in claim 10,wherein each of the connecting members is designed so that it can bepushed by its front end into an associated one of the crash boxelements, by its rear end into an associated one of the longitudinalmembers, or both by its front end into the associated one of the crashbox elements and by its rear end into an associated one of thelongitudinal members.
 13. The front-end vehicle structure as claimed inclaim 12, wherein each of the connecting members and the longitudinalmembers has a C-profile, and wherein an external size of each respectiveconnecting member corresponds, in an assembled state, with an internalsize of a respective one of the longitudinal members.
 14. The front-endvehicle structure as claimed in claim 10, wherein the inner part, theupper part, and the lower part are connected by welds extending alongthe bent-over edge sections.
 15. The front-end vehicle structure asclaimed in claim 10, wherein the inner part, the upper part, and thelower part can be formed with identical or different sheet-metalthicknesses.
 16. The front-end vehicle structure as claimed in claim 10,wherein the edge sections are separated from one another by incisions.17. The front-end vehicle structure as claimed in claim 10, wherein theconnecting members are reinforced by brackets, wherein one of saidbrackets is arranged on each inner part, and wherein each bracket isdesigned for reinforcing at least one of the connecting members.
 18. Thefront-end vehicle structure as claimed in claim 10, wherein thefront-end vehicle structure is designed, in a region of the connectingmembers, for receiving a rigid axle or an individual wheel suspension.19. The front-end vehicle structure as claimed in claim 11, wherein eachof the connecting members is designed so that it can be pushed by itsfront end into an associated one of the crash box elements, by its rearend into an associated one of the longitudinal members, or both by itsfront end into the associated one of the crash box elements and by itsrear end into an associated one of the longitudinal members.
 20. Thefront-end vehicle structure as claimed in claim 11, wherein the innerpart, the upper part, and the lower part are connected by weldsextending along the bent-over edge sections.
 21. The front-end vehiclestructure as claimed in claim 11, wherein the inner part, the upperpart, and the lower part can be formed with identical or differentsheet-metal thicknesses.
 22. The front-end vehicle structure as claimedin claim 11, wherein the edge sections are separated from one another byincisions.
 23. The front-end vehicle structure as claimed in claim 11,wherein the connecting members are reinforced by brackets, wherein oneof said brackets is arranged on each inner part, and wherein eachbracket is designed for reinforcing at least one of the connectingmembers.
 24. The front-end vehicle structure as claimed in claim 11,wherein the front-end vehicle structure is designed, in a region of theconnecting members, for receiving a rigid axle or an individual wheelsuspension.
 25. The front-end vehicle structure as claimed in claim 12,wherein the inner part, the upper part, and the lower part are connectedby welds extending along the bent-over edge sections.
 26. The front-endvehicle structure as claimed in claim 12, wherein the inner part, theupper part, and the lower part can be formed with identical or differentsheet-metal thicknesses.
 27. The front-end vehicle structure as claimedin claim 12, wherein the edge sections are separated from one another byincisions.
 28. The front-end vehicle structure as claimed in claim 12,wherein the connecting members are reinforced by brackets, wherein oneof said brackets is arranged on each inner part, and wherein eachbracket is designed for reinforcing at least one of the connectingmembers.
 29. The front-end vehicle structure as claimed in claim 12,wherein the front-end vehicle structure is designed, in a region of theconnecting members, for receiving a rigid axle or an individual wheelsuspension.